Prospective memory and quality of life in older and younger autistic adults

Ageing in late adulthood is generally accompanied by diminished prospective memory (PM), which itself is associated with declining quality of life (QoL). Given that autistic individuals are often reported as having PM difficulties and diminished QoL, we aimed to establish whether these measures are also associated in these individuals as they grow older. We administered questionnaire measures of prospective and retrospective memory (PM and RM) and of overall and health-related quality of life (QoL) and experimental measures of time-based and event-based PM (TBPM and EBPM) to 35 autistic and 22 non-autistic adults aged from 23 to 80 years. The autistic participants reported higher levels of PM and RM difficulties than non-autistic participants but that these reports did not correlate with age nor with the experimental TBPM or EBPM measures in either group. Age correlated negatively with two of the experimental measures of TBPM for the non-autistic participants, replicating earlier studies. Autistic participants showed diminished performance on the TBPM but not the EBPM measures, replicating the majority of earlier PM studies in autism. Autistic participants also reported lower overall and health-related QoL, but there were no age-related differences for either measure in either diagnostic group. Self-reported PM and RM correlated significantly with health-related QoL in both the autistic and non-autistic participants. Overall QoL was positively associated with TBPM accuracy in the non-autistic participants. In addition to confirming earlier findings showing that autistic individuals have greater difficulties with TBPM compared to EBPM, our findings suggest that neither EBPM nor TBPM difficulties appear to adversely affect their overall or health-related QoL. The patterning of the autistic participants' results also suggests that the mechanisms underlying their performance on the tasks used in this study may differ from those of the non-autistic participants, pointing to the need for careful task analysis when designing future investigations.